Distinguishing FF vs non-FF updates in the reflog?

From: Han-Wen Nienhuys <hanwen@google.com>
Date: Mar 17, 2021, 20:06 UTC
Message-ID: <CAFQ2z_MefCwiWdhs0buJv5Zok+nsgaOvUCcsSnfm_PP0WozZKA@mail.gmail.com>

Hi there,

I'm working on some extensions to Gerrit for which it would be very beneficial if we could tell from the reflog if an update is a fast-forward or not: if we find a SHA1 in the reflog, and see there were only FF updates since, we can be sure that the SHA1 is reachable from the branch, without having to open packfiles and decode commits.

For the reftable format, I think we could store this easily by introducing more record types. Today we have 0 = deletion, 1 = update, and we could add 2 = FF update, 3 = non-FF update.

However, the textual reflog format doesn't easily allow for this. However, we might add a convention, eg. have the message start with 'FF' or 'NFF' depending on the nature of the update.

Does this make sense, and if yes is it worth proposing a change?

thanks,

-- 
Han-Wen Nienhuys - Google Munich
I work 80%. Don't expect answers from me on Fridays.
--

Google Germany GmbH, Erika-Mann-Strasse 33, 80636 Munich

Registergericht und -nummer: Hamburg, HRB 86891

Sitz der Gesellschaft: Hamburg

Geschäftsführer: Paul Manicle, Halimah DeLaine Prado